When Google (Nasdaq: GOOG) introduced Google Voice (GV) for the iPhone last month, it was a brilliant stroke for Apple (Nasdaq: AAPL).

Allowing GV to exist on iOS devices eliminates what may be the biggest reason a heavy user of The Big G's services (e.g., me) would switch to Android from the iPhone.

Battle of the brands
To be fair, the majority of iPhone owners never get that far. Germany's Gfk Group recently surveyed 2,653 smartphone owners and found that 59% planned to stay with the iPhone when upgrading.

Users of Research In Motion's (Nasdaq: RIMM) BlackBerry ranked second, with 35% of users saying they'll stay with RIM. Only 28% of Android users said they wouldn't switch, while 24% of Nokia (NYSE: NOK) owners said they'd stick with the brand.

Judging by the numbers, Apple is clearly the brand leader. But 41% of all iPhone owners would still equal tens of millions toying with the idea of switching. Not long ago, you could have counted me among that group -- despite my history as a very happy 2G user.

Why? I've invested too much in Gmail, Google Calendar, and Google Voice to not get the very best versions of these apps working on my smartphone. With GV now available for the latest iOS, this is no longer an issue.

Here's what the app gives me that I've long been craving:

  1. Free texting. Now that AT&T (NYSE: T) and Verizon (NYSE: VZ) embraced more tiered data plans based on usage, supporting GV and services such as Skype aren't as painful as they might have otherwise been. I win by paying just the bare minimum in texting charges.
  2. Integrated contacts. Before, if I wanted access to my Google Contacts on the iPhone, I'd have to customize the settings -- and even then I'd only get access to those on the "My Contacts" discrete list in Gmail. GV includes a search feature connected to Gmail that finds any contact in the database, regardless of how they're categorized. Call it a touch of Google doing what Google does best.
  3. Simple access to recorded calls and voice mail. The GV menu has links to every type of call I make or receive with the service. That way, I can get to recorded calls, voice mails, etc., without having to sync with iTunes.

I'll grant that Google Voice isn't for everyone, but the service is free to use through at least the end of 2011. Millions have adopted it already. Thousands more may adopt it now that it's on the iPhone.

Now it's your turn to weigh in. Are you using Google Voice on the iPhone? Please vote in the poll below and then leave a comment to explain your choice. You can also rate Google in Motley Fool CAPS.

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Fool contributor Tim Beyers is a member of the Rule Breakers stock-picking team. He had stock and options positions in Apple and a stock position in Google at the time of publication. Check out Tim's portfolio holdings and Foolish writings, or connect with him on Twitter as @milehighfool. You can also get his insights delivered directly to your RSS reader. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool owns shares of Apple and Google and is also on Twitter as @TheMotleyFool. Its disclosure policy needs someone to shovel the driveway. What do you say, Fool?